1. Field of the Invention
The present invention relates to a control interface for a data terminal such as a personal computer connected to a network.
2. Related Art
Developments in telecommunications and computing, such as the growth of the Internet, potentially make available to users a large and diverse universe of data. It is important therefore that any data terminal is designed in such a way as to facilitate efficient browsing, selection and retrieval of data. It has long been recognised that the nature of the user interface makes an important contribution to the operational efficiency of any such terminal. User interfaces have developed from simple text-based command line interfaces to two-dimensional graphic user interfaces (GUI's) such as those associated with the industry-standard operating systems of Apple Computers, Microsoft and others. In two-dimensional GUI's data are commonly displayed and accessed in a tree structure using a file and folder metaphor. As the size and complexity of the available data increases, such an approach becomes increasingly inadequate.
It has recently been proposed to use interfaces based on a three-dimensional display and control environment. In such an environment, a data source--which may be, for example a file on a local storage device, a remotely located file, or a live data source such as an on-line news service--is typically represented as a three-dimensional object in a landscape. The visual characteristics of the object may be used to identify the type of data, and the relative positions of different objects may be used to map relationships between the data. The user traverses the landscape and interacts with the data using an input device such as a mouse.
The use of a three-dimensional interface provides additional ways of indicating to the user relationships between data, and opens up the possibility of a variety of new forms of interaction between the user and the terminal. It is found however that the greater complexity of the 3-D interface can easily exacerbate the demands placed on the user. Many of the cues which aid human navigation in the real world are missing in the 3-D environment, and the input device used for control of the viewpoint in the environment may be unfamiliar and difficult to use. Slow system response compounds these problems. The user may find that after performing some control action using the input device the viewpoint changes in an unexpected way. The user may end up looking at an unfamiliar or unpopulated part of the environment, with no obvious way of returning to the region containing data sources of interest. In view of these problems, unless the behaviour of the 3-D user interface is appropriately controlled it may reduce rather than increase the efficiency with which the terminal can be used to access data.